"What a sensational idea!
Public interactive art!
Of course we need tic-tac-toe installations!

Just make them flat and safe to walk on and over.
Perhaps they could also be placed in heavily trafficked areas so that pedestrians can begin to reclaim the public thoroughfares in the center of the city!

I can see it now, "Boston 2024! First International Street Tic-Tac-Toe Competition"!